Wednesday, December 03, 2008

Creationists take aim at neuroscience (1): defining their target

A recent opinion piece in New Scientist, Creationists declare war over the brain, discusses the natural alignment between antievolutionists and those that think the human mind (in particular consciousness) is forever outside the explanatory reach of neuroscience. The topic of consciousness tends to bring out the nutballs, and creationism ties people's knickers in knots, so the article has received a good deal of attention from the internet commentariat.

Since I've thought about this topic way too much, I thought I'd throw my crap into the ring too. I'll discuss the arguments of the neodualists indirectly at first, dividing my discussion of consciousness into multiple posts. Because 'consciousness' is a dirty word in some neuroscience quarters, in this post I'll clear the air by clarifying what I mean by the term.

What is consciousness?What are you experiencing right now? For instance, are you aware of hunger pangs in your gut, words on a screen, the deep red hues of a freshly picked rose? 'Consciousness' is just another word for this ability to perceive or be aware of the world. Indeed, for those who want to avoid the C-word, 'awareness' is a perfectly good synonym.

The canonical instances of conscious awareness are moments when we are awake, alert, and attending to something interesting such as a sunset. However, even while dreaming we are conscious of something, perhaps a sort of neuronal simulation of the world.

Should scientists bother with consciousness?Over beers many neuroscientists are dismissive when consciousness comes up. They treat it as a "philosophical" problem, a waste of time for real scientists. I find this attitude strange. New data fuel conceptual progress in science, so it seems an empirical approach is the best way to make headway on something that is clearly a real and important phenomenon. Avoiding the topic leaves it in the hands of the philosophers, a fate just a little better than death.

I suppose one could argue that there is no way to study consciousness experimentally because it is inherently subjective or something. This argument doesn't work, though, as there already exist fairly straightforward experimental probes of consciousness. For example, binocular rivalry. If you show a different image to each eye (see example rivalrous stimulus below), you don't see a fusion of the two images. Rather, you perceive the images one at a time (a dog then a cat, not a dog-cat). Neuroscientists can compare the bits of the brain that track the eye-locked stimuli (which stay the same) with those that oscillate with the visual percept. This has provided a useful roadmap that tells us which parts of the brain are locked to the stimulus, and which shift with the object of conscious awareness.

The dismissive types are typically either unfamiliar with such experimental paradigms, or they tend to be skeptical of all research with a psychological component. For the former, Koch's book The Quest for Consciousness gives a nice summary of many experiments. For those skeptical of all cognitive neuroscience, there isn't much to be done (frankly, I am sympathetic to general skepticism toward cognitive neuroscience, which is a very speculative discipline right now). Hence, my take-home argument is that consciousness is just as legitimate (or illegitimate) a research topic as more mainstream psychological phenomena like attention and memory.

I should add one caveat. I have been writing as if all uses of the term 'consciousness' refer to the same thing. This may be false. Perhaps there are separate mechanisms for different sensory modalities. Or even within a modality: for instance, there could be different mechanisms for awareness of things in the center versus the periphery of our visual field. Maybe the mechanisms that underlie dreaming have little overlap with waking awareness. It could be that 'consciousness' is a mongrel term like 'memory,' and it will splinter as the science progresses.

My next post will begin describing what a biological approach to consciousness would look like.

I am looking foward to more- you seem to have a good attitude toward this subject.It is possible to study things we can't see directly (has anyone ever seen gravity?) and we can learn much by doing so.

You are writing very ambiguously here. I am not sure how familiar you are with the philosophy of consciousness (your "definition" it is very controversial in philosophy and cannot be all there is to 'consciousness'), but I would wager you have little background in it.

Anyway back to the ambiguity: even though there are many prominent philosophical dualists (or non-reductionists or anti-physicalists), I would say that NONE of them are creationists and think creationism is poppycock. Are you parrying creationists/dualists or philosophical dualism? If the former, well, shooting fish in a barrel is sport for some. If the latter, then your definition of consciousness belies a immature understanding of the copious positions.

And watching scientists think they can do good philosophy is rarely done well (I will refrain from analogies to death here).

'Consciousness' is just another word for this ability to perceive or be aware of the world. Indeed, for those who want to avoid the C-word, 'awareness' is a perfectly good synonym.

I don't think it's just that. You could have a system that has 'perception' and 'awareness' in a purely functional sense because of the information processing it does, without it having any subjective 'first-person' experience -- without it being like anything to be that system (as Thomas Nagel might say).

This subjective first-person experience seems to be clearly something else/more than simply information processing (this of course is not to say that we can therefore assume it is something mystical).

So far I've been completely neutral about the basis of this consciousness/awareness/subjective experience. I've just pointed to the phenomenon, not tried to explain it. It is not even well characterized empirically yet, so it would be premature for me to do so.

Prior to having a fully satisfactory definition or even rudimentary explanation, we can still probe consciousness experimentally as in binocular rivalry. Indeed, the main problem with philosophers is that they push for prematurely precise characterizations of what the scientists are just starting to study. Imagine if biologists had spent all their time trying to define 'life' instead of just studying life? Even now there isn't a great definition of life out there, but there sure is a lot of great biology. This highlights the deep methodological differences between science and (most) philosophy, and is why I made that quip about philosophers in my post.

If awareness is a perfect synonym for conciousness what about arousal?

I say this becuase many neurologists approaching what is called "disorders of conciousness" differentiate in consciousness two dimensions: awareness and arousal (a.k.a.; the content of consciouness and the level of conciousness)

I’m not trying to suggest you should have to define it. I don’t think that, when faced with an unexplained phenomenon, our task is to try and define it. Our task should be to try and understand what’s going on. I think that trying to define something without really understanding it is likely to just lead to pointless arguments about words.

I’m trying to make the point that ‘perception’ or ‘awareness’, taken in purely ‘information processing’ terms, can be (and FWIW, I think often are) taken as the be-all of consciousness – thus effectively acting as there’s nothing additional that needs to be accounted for on top of those things to account for subjective first-person experience.

I think the ‘experimental probing of consciousness’ that you refer to is only dealing with the purely functional, information-processing aspect. Or at least that is all it is telling us about. It is possible that we may get clues about the nature of subjective first-person experience from them, but this is by no means guaranteed.

There’s no way to tell, from the results, whether there actually was subjective first-person experience present in the test subject. Of course, we assume there is in the case of people. We’d feel less certain in the case of various types of animals. But in any case, there’s nothing from those experiments that we know we can feed into our judgements about these matters.

Anibal: I wouldn't want to say arousal and awareness are synonyms. Arousal is a more general thing like being awake, a sort of measure of how much general energy and motivation you have. I look at arousal as a kind of measure of how high the volume knob is on our sympathetic nervous system.

James:I think the ‘experimental probing of consciousness’ that you refer to is only dealing with the purely functional, information-processing aspect.

You are assuming that there is more to consciousness than some "purely" functional or information processing story. Right now I'm not focusing on the basis of consciousness, but just characterizing it. One problem with talk of consciousness is that people want to jump the gun and blurt out their favorite theory. Slow down, I haven't gone there yet.

The point of this post is much more mundane than all that, and is orthogonal to the philosophical schools. In rivalry, what we see toggles back and forth. We can be substance dualists, panpsychists, materialists, whatever, and still study rivalry experimentally, and all agree we are studying consciousness. The philosophical differences won't affect our data, but only our interpretation of the behavioral and neural data acquired during the psychophysical tasks.

There’s no way to tell, from the results, whether there actually was subjective first-person experience present in the test subject.

A good point. It could be that when the subject says they see the cat/dog they are not actually seeing the cat/dog.

In the most boring case, they are lying. This is the easy one: insert 'trap' trials where a dog is shown to both eyes without them knowing it. If they say they see a cat, they are not a reliable subject.

Even worse, you could say they aren't even lying, but unconscious automata spitting out verbal reports like a stock ticker. I suppose I'm assuming if we are dealing with two people this isn't the case, and there are ways to know if we are dealing with people or automata. Luckily, it seems you agree.

The case of animal consciousness is interesting and I plan to discuss it in a future episode.

“You are assuming that there is more to consciousness than some "purely" functional or information processing story.”

Let me try and rephrase then: there is nothing in our present understanding of ‘information processing’ that even comes close to hinting at what subjective first-person experience is.

Does this therefore mean that the explanation of subjective first-person experience can not be a matter of information processing (or information processing plus something else)? I think you’re right to say that we can’t rule out the possibility that information processing may be in the explanation.

At the same time, we also can’t assume that the information processing is part of the subjective first-person experience. It no doubt provides some sort of ‘input’ to it, but we have no evidence at all that it is actually part of it.

“We can be substance dualists, panpsychists, materialists, whatever, and still study rivalry experimentally, and all agree we are studying consciousness.”

Yes, that’s studying stuff to do with consciousness, but my point is that we can not make the claim that this is telling us anything about what subjective first-person experience is. It may actually be doing so, but if it is we certainly do not yet have any evidence that it is.

All along (i.e. in all my comments here), I’ve just been trying to make a point of disagreement with a statement you made in the original post:

“'Consciousness' is just another word for this ability to perceive or be aware of the world. Indeed, for those who want to avoid the C-word, 'awareness' is a perfectly good synonym.”

- my point of disagreement being that you can’t say that consciousness is just perception or awareness, unless you acknowledge that that perception/awareness involves some sort of first-person subjective experience. In my initial reading of your statement, I didn’t think were including it (a lot of people seem to assume that information processing just somehow can account for subjective first person experience -- without giving any explanation of how it is supposed to do so), but perhaps I wasn’t reading it as you intended.

And just to reiterate, I don't think that because subjective-first person experience appears to be mysterious, it must therefore somehow have "mysterious causes".

James:My initial definition is inclusive of any view of the nature of awareness and experience. That is, I don't exclude the 'first person' perspective (if that's how you want to put it), and don't exclude your view if you think awareness/experience is 'subjective' that's fine (I'm not sure what you mean by that exactly, but if it is consistent with experiencing a red rose then what have I excluded?).

I avoid describing consciousness using the phrase 'first person' as that is a fairly mundane grammatical category. 'I fell off my bike' is first person too. I know you realize this as you put it in quotes. I also know it is very common in philosophy.

At any rate I don't see any disagreement between us. I've said very little so far. I'll give plenty to disagree with in later posts.

For your consideration, here's my first-pass definition of consciousness that I posted on the *Nature* forum aimed at arriving at a useful definition. It seems to be ending inconclusively. At any rate, this is what I find helpful now:

*Consciousness is a transparent phenomenal experience of the world from a privileged egocentric perspective.*

Arnold: interesting, but I think as a first pass characterization (say, one you would use to describe what you are working on to your grandma or something) it's a bit esoteric.

There aren't any foolproof definitions out there that I've seen. They all invoke equally mysterious synonyms (e.g., 'phenomenal experience'). I think to focus too much on definitions is a mistake anyway, for reasons I mentioned in a previous comment. My goal here was to get people on the same page as far as what I was talking about, especially those that think consciousness is BS.

I agree that scientists can study consciousness to some extent, but until there is an objective test for consciousness that study is incomplete. Studying binocular rivalry gives us a clue to what a person is conscious of, but that is not the same as a study of consciousness directly.This is an important point as scientists are famous for 'knowing it all'. (Nobody questioned Newton for centuries- 'we know all of physics' was one reason- check any history of Max Planck)Until you can tell me with certainty if a person, a chimp, a dog, a snake, a bird, a tree and a bacterium are conscious or not (I would say they all are BTW), part of what you are studying is outside of science.

Anonymous: such criteria should come after the science has progressed. It has to start somewhere, and we are early in the science. What are the set of conditions to be used to know if a creature uses a language? Did we have to know that before we began to study language scientically? No, but that didn't mean early students of language weren't doing science.

We could say the same thing about early students of digestion, photosynthesis, etc.. The rigorous criteria come as the science progresses, are not there before the science has hardly begun!

I'll be discussing non-human consciousness in a post in the future, though.